In order to estimate a lifetime of a secondary battery during development of the secondary battery, charge and discharge operations are repeatedly performed under various conditions and time periods, which are similar to those for a case where the secondary battery is actually used, and a lifetime of the secondary battery is estimated by measuring a cycle life (residual capacity ratio) whenever measurement is made.
An amount of time required for evaluating the cycle life of the secondary battery is approximately 50% or greater of the entire amount of time required for the development of the secondary battery. Thus, the evaluation of the cycle life of the secondary battery is an important factor in reducing the amount of time required for the development of the secondary battery.
In particular, in view of the short product cycle of the IT fields as compared to products of other fields, it is quite desirable to reduce the amount of time for cycle life evaluation.